As the demand for heat stability of materials to be used in automobile engines increases, gaskets made of silicone rubber have been broadly used for sealing of an engine and its surroundings. In particular, formed-in-place gaskets (hereinafter referred to as "FIPG") made from a room temperature-curable liquid silicone rubber have been replacing conventional cut-to-size gaskets for ease of inventory control of gaskets, ease of process control in production of engines, and high reliability of sealing performance. The advantages of the FIPG system in workability, heat resistance, and the like are now highly estimated.
Since the engine parts to be sealed are often contaminated with organic oily substances such as hydrocarbon oils, animal or vegetable oils, and synthetic oils as in the case that a rust preventing oil is applied or that the parts are dipped in an engine oil for smooth assembly, the oily contaminants must be wiped off the surface with a cloth, etc. before FIPG sealing. However, since the organic oily substances, such as hydrocarbon oils, are not completely removed, the parts cannot be sealed completely. For example, should an oil pan with its surface contaminated be sealed by an FIPG system, cases are sometimes met with in which troubles, such as leakage of an engine oil, occurs in use. Further, while an FIPG sealing compound is automatically coated by means of a robot, the above-described wiping operation with a cloth is manually conducted, which has been a bar to automation of a series of operations.
In order to settle these problems, WO 88/500178 (unexamined published international patent application) discloses an adhesive comprising a room temperature-curable organopolysiloxane composition and an oxime(alkoxy)silylalkylurea compound as a fixing agent. However, use of such a fixing agent still fails to make the composition adhesive to an oil-contaminated surface and to solve the outstanding problems.